Chemical vapor deposition of silicon dioxide films has been employed in semiconductor fabrication for several years. Such films have been produced by using, for example, conveyorized atmospheric pressure chemical vapor deposition (APCVD) apparatus. An exemplary APCVD device is disclosed in U.S. Pat. No. 4,834,020, entitled "Atmospheric Chemical Vapor Deposition Apparatus", which is assigned to the assignee of the present invention, and which is herein incorporated by reference.
In the early development of silicon dioxide films silane and oxygen were often used as source gases. Unfortunately, the use of particular deposition precursors in these initial efforts tended to impede film conformance to various types of surface features. Organosilane precursors such as tetraethylorthosilicate (TEOS) have since been used to improve surface conformity, but have generally required relatively high deposition temperatures.
In recently developed techniques, ozonated oxygen has been employed as a source gas with TEOS and other organosilane precursors in order to obtain deposition of silicon dioxide at reduced temperatures (300.degree.-500.degree. C.). As is known, the use of ozonated oxygen allows deposition to be initiated at low temperatures without requiring plasma excitation. Films created using these recently developed techniques have generally exhibited improved topographical conformance, thereby enabling the production of films with smooth surfaces. However, such films often do not readily grow upon commonly encountered surfaces such as thermal silicon dioxide or fluorine-contaminated metals. Such inhibition of nucleation can result in reduced deposition rates and increased film porosity.